Discharging a firearm causes gases to be produced through rapid, confined burning of a propellant that accelerates a projectile. This typically creates a loud noise and a muzzle flash of light. Often, it is desirable to reduce the amount of noise and light produced by discharging a firearm. For example, military snipers or special operations forces personnel may require stealth to successfully complete missions. Suppressors, or silencers, are typically connected to the muzzle end of a firearm to temporarily capture gas that exits the muzzle. Some suppressor designs divert a portion of the discharge gas to a secondary chamber, such that the gas does not exit the suppressor by the same path as the projectile. The gas is released from the suppressor at a significantly reduced pressure. In general, the more gas a suppressor captures, the quieter the discharge sound of the firearm.
The presence of a suppressor, however, may increase the back pressure of the gas in the barrel of the firearm. Increased back pressure in the barrel can influence the firearm's operation. For example, some firearms are gas-operated and use discharge gas pressure in the barrel to reload the firearm. Thus, increasing gas back pressure in the barrel can increase forces acting on the reloading components.
Higher forces can reduce the service life of the reloading components. However, for certain ammunition types, reloading performance may improve with increased barrel back pressure. Additionally, certain tactical situations may dictate maximum suppression of the discharge of the firearm. This can result in maximum forces on the reloading components. Such a condition may be feasible for a limited number of firings before failure of the reloading components is likely to occur.